As is known in the art, owners and operators of large vehicle fleets invest significant amounts of operating cash in yearly fuel costs. One source of previously uncontrollable cost is fuel spent on vehicles left in an idle state while the driver is engaged in other activities. To address green house emissions, recent regulations in CARB regulated states now require vehicles over 14,000 lbs to meet certain diesel emissions standards or implement some type of idle control shutdown strategy which may include engine shutdown after certain conditions are met. One immediate problem is what to do after the vehicle engine has been shutdown. This immediate problem is associated with the fact that the vehicle ignition switch is still left in the ON or RUN position by the driver and the entire electrical system is draining the battery. If left unattended the battery would drain in as little as 2 hours and the vehicle would be unable to start. Repeated deep-cycling of the battery in such a circumstance would lead to reduced battery life and increased battery warranty. Additionally, owner/operator product dissatisfaction could be significant.
In view of the foregoing the inventors have recognized that a need exists to have a system within a vehicle that provides for simulating turning off the ignition switch even though it is still in the ON or RUN position while preserving battery life in the case where an idle shutdown strategy has been executed.
In accordance with the present invention, a method is provided for preserving battery operation and life during post vehicle idle shutdown, such vehicle having a delayed accessory power mode becoming operative when an ignition state of the vehicle is in a non-engine running condition while the ignition switch of the vehicle is in the ON or RUN position to supply accessories in the vehicle the battery. The method includes: detecting whether the vehicle has been in a post idle shutdown and the brake has not been pressed or ignition status unchanged; and then placing the vehicle in the delayed accessory power mode after detecting that the vehicle has been in a the post idle shutdown condition while the ignition switch is in the ON or RUN position.
In one embodiment, after placing the vehicle in the delayed accessory power mode after detecting that the vehicle has been in a post idle shutdown condition, the mode is returned to a previous mode in response to a vehicle operator either changing the brake pedal state or changing vehicle ignition state.
In one embodiment, the detecting uses network message information indicating engine status; brake pedal state; and ignition key position.
In one embodiment, engine state is either ON as when the engine is either running in an idle condition or OFF as when the engine is in the non-running condition.
In one embodiment, information includes door ajar signals.
Such method provides an architecturally integrated passive solution that has the advantages of meeting rigorous automotive validation standards. The solution is also designed to be “inserted” into the primary power feeds without a major disruption in existing wiring harness design and manufacturing impact. Solution enhancement of network allows for provisions to provide vehicle message such as door ajar to promote lights out feature from vehicle delay accessory providing addition battery saving capability.
The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.
Like reference symbols in the various drawings indicate like elements.